Fix 1.8 link (#2174)

* fix dead link

* test=develop

doc/fluid/install/install_CentOS.md

@@ -56,7 +56,7 @@
         python3 -c "import platform;print(platform.architecture()[0]);print(platform.machine())"
 
 * 默认提供的安装包需要计算机支持MKL
-* 如果您对机器环境不了解，请下载使用[快速安装脚本](https://fast-install.bj.bcebos.com/fast_install.sh)，配套说明请参考[这里](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install).
+* 如果您对机器环境不了解，请下载使用[快速安装脚本](https://fast-install.bj.bcebos.com/fast_install.sh)，配套说明请参考[这里](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install/install_script.md).
 
 ## 选择CPU/GPU
 

doc/fluid/install/install_CentOS_en.md

@@ -57,7 +57,7 @@
         python3 -c "import platform;print(platform.architecture()[0]);print(platform.machine())"
 
 * The installation package provided by default requires computer support for MKL
-* If you do not know the machine environment, please download and use[Quick install script](https://fast-install.bj.bcebos.com/fast_install.sh), for instructions please refer to[here](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install).
+* If you do not know the machine environment, please download and use[Quick install script](https://fast-install.bj.bcebos.com/fast_install.sh), for instructions please refer to[here](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install/install_script.md).
 
 ## Choose CPU/GPU
 

doc/fluid/install/install_Ubuntu.md

@@ -57,7 +57,7 @@
         python3 -c "import platform;print(platform.architecture()[0]);print(platform.machine())"
 
 * 默认提供的安装包需要计算机支持MKL
-* 如果您对机器环境不了解，请下载使用[快速安装脚本](https://fast-install.bj.bcebos.com/fast_install.sh)，配套说明请参考[这里](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install).
+* 如果您对机器环境不了解，请下载使用[快速安装脚本](https://fast-install.bj.bcebos.com/fast_install.sh)，配套说明请参考[这里](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install/install_script.md).
 
 ## 选择CPU/GPU
 

doc/fluid/install/install_Ubuntu_en.md

@@ -57,7 +57,7 @@
         python3 -c "import platform;print(platform.architecture()[0]);print(platform.machine())"
 
 * The installation package provided by default requires computer support for MKL
-* If you do not know the machine environment, please download and use[Quick install script](https://fast-install.bj.bcebos.com/fast_install.sh), please refer to[here](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install).
+* If you do not know the machine environment, please download and use[Quick install script](https://fast-install.bj.bcebos.com/fast_install.sh), please refer to[here](https://github.com/PaddlePaddle/FluidDoc/tree/develop/doc/fluid/install/install_script.md).
 
 ## Choose CPU/GPU